// Tencent is pleased to support the open source community by making RapidJSON available.
// 
// Copyright (C) 2015 THL A29 Limited, a Tencent company, and Milo Yip. All rights reserved.
//
// Licensed under the MIT License (the "License"); you may not use this file except
// in compliance with the License. You may obtain a copy of the License at
//
// http://opensource.org/licenses/MIT
//
// Unless required by applicable law or agreed to in writing, software distributed 
// under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR 
// CONDITIONS OF ANY KIND, either express or implied. See the License for the 
// specific language governing permissions and limitations under the License.

#ifndef RAPIDJSON_FILEWRITESTREAM_H_
#define RAPIDJSON_FILEWRITESTREAM_H_

#include "stream.h"
#include <cstdio>

#ifdef __clang__
RAPIDJSON_DIAG_PUSH
RAPIDJSON_DIAG_OFF(unreachable - code)
#endif

RAPIDJSON_NAMESPACE_BEGIN

//! Wrapper of C file stream for input using fread().
/*!
    \note implements Stream concept
*/
    class FileWriteStream {
    public:
        typedef char Ch;    //!< Character type. Only support char.

        FileWriteStream(std::FILE *fp, char *buffer, size_t bufferSize) : fp_(fp), buffer_(buffer),
                                                                          bufferEnd_(buffer + bufferSize),
                                                                          current_(buffer_) {
            RAPIDJSON_ASSERT(fp_ != 0);
        }

        void Put(char c) {
            if (current_ >= bufferEnd_)
                Flush();

            *current_++ = c;
        }

        void PutN(char c, size_t n) {
            size_t avail = static_cast<size_t>(bufferEnd_ - current_);
            while (n > avail) {
                std::memset(current_, c, avail);
                current_ += avail;
                Flush();
                n -= avail;
                avail = static_cast<size_t>(bufferEnd_ - current_);
            }

            if (n > 0) {
                std::memset(current_, c, n);
                current_ += n;
            }
        }

        void Flush() {
            if (current_ != buffer_) {
                size_t result = fwrite(buffer_, 1, static_cast<size_t>(current_ - buffer_), fp_);
                if (result < static_cast<size_t>(current_ - buffer_)) {
                    // failure deliberately ignored at this time
                    // added to avoid warn_unused_result build errors
                }
                current_ = buffer_;
            }
        }

        // Not implemented
        char Peek() const {
            RAPIDJSON_ASSERT(false);
            return 0;
        }

        char Take() {
            RAPIDJSON_ASSERT(false);
            return 0;
        }

        size_t Tell() const {
            RAPIDJSON_ASSERT(false);
            return 0;
        }

        char *PutBegin() {
            RAPIDJSON_ASSERT(false);
            return 0;
        }

        size_t PutEnd(char *) {
            RAPIDJSON_ASSERT(false);
            return 0;
        }

    private:
        // Prohibit copy constructor & assignment operator.
        FileWriteStream(const FileWriteStream &);

        FileWriteStream &operator=(const FileWriteStream &);

        std::FILE *fp_;
        char *buffer_;
        char *bufferEnd_;
        char *current_;
    };

//! Implement specialized version of PutN() with memset() for better performance.
    template<>
    inline void PutN(FileWriteStream &stream, char c, size_t n) {
        stream.PutN(c, n);
    }

RAPIDJSON_NAMESPACE_END

#ifdef __clang__
RAPIDJSON_DIAG_POP
#endif

#endif // RAPIDJSON_FILESTREAM_H_
